The present invention relates to a GPS receiving system, a Global Positioning System (GPS) receiver and a recording medium therefor and more particularly, to an input/output interface (I/F) structure of the GPS receiver and input/output I/F software therefor. The present invention also concerns a structure of a position measuring data network for a GPS application system, a method for wiring a network, and an operating system of operational control.
In a conventional PGS receiver, RS-232C for one-to-one communication has been supported as an input/output I/F, thereby realizing data transmission and reception. In this way, the conventional receiver only supports the RS-232C of the one-to-one communication. Thus when it is desired to form a monitor system for performing position monitoring operation with use of a plurality of GPS receivers, it has been necessary to connect a personal computer (PC) with the receivers each in a one-to-one (1:1) connection relationship therewith with use of a card with a plurality serial ports or to connect a plurality of PC""s with the receivers each in a one-to-one connection relationship, as shown in FIGS. 9A, 9B, 10A and 10B. For this reason, RS-232C cables corresponding in number to the GPS receivers become necessary and it is required to record or log GPS data at upper-level computers having a plurality of RS-232C ports or to connect the GPS receivers with upper-level computers corresponding in number to the GPS receivers in a one-to-one connection relationship for logging of the GPS data. Further, this also involves a high cost for the system formation since a cable pipe for housing the RS-232C serial cables inevitably must be made large, etc.
Use of an input/output interface (I/F) other than the RS-232C has been suggested. For example, refer to JP-A-10-115676, JP-A-10-26660 and JP-A-7-294624. However, any of these proposals fails to use a plurality of GPS receivers in a system. Further, when GPS receivers are used in a communication network such as Ethernet typical of LAN, it is necessary to additionally provide a protocol converter between TCP/IP and RS-232C. And when a GPS receiver having only a 10 BASE-T port is used, the LAN becomes of a star type connection and thus LAN cables are concentrated on a hub part. For this reason, when GPS receivers are used for long-distance linearity monitoring such as monitoring of continuous wall surface, the number of cables to be bound becomes many and a thick electric pipe therefor becomes necessary as in the case of routing RS-232C cables, thus resulting in a high cost for system formation.
FIGS. 9A and 9B show an arrangement of a system as a prior art 1 of an RS-232C one-to-one connection type, e.g., for realizing wall surface linearity monitoring by means of RS-232C connection. FIG. 9A shows an arrangement when one-to-one connection is realized with use of a card having a plurality of serial ports, while FIG. 9B shows an arrangement when one-to-one connection is realized with use of a plurality of PC""s. The former is the system configuration when a PC 3xe2x80x2 for GPS data logging is connected to GPS receivers 1axe2x80x2 to 1dxe2x80x2 having GPS antennas 2axe2x80x2 to 2dxe2x80x2 via RS-232C cables 5axe2x80x2 to 5dxe2x80x2 respectively. When the second, third and fourth GPS receivers 1bxe2x80x2, 1cxe2x80x2 and 1dxe2x80x2 are connected with use of the RS-232C cables 5bxe2x80x2 to 5dxe2x80x2 of 1:1 communication, this means that the necessary number of such cables corresponds to the number of such GPS receivers, which makes it difficult to form a system since the laying of cables is restricted, the PC 3xe2x80x2 is required to have a plurality of serial ports, etc. Further, the maximum number of such GPS receivers capable of being connected to the number of serial ports is restricted, which becomes demerit upon formation of the system. In the latter case, the PC""s 3axe2x80x2 to 3dxe2x80x2 are required by the number corresponding to the number of such GPS receivers 1axe2x80x2 to 1dxe2x80x2, which results in a high cost formation of the system as a demerit.
FIGS. 10A and 10B show, as a system of a prior art 2, a system based on external hub connection of 10 BASE-T, e.g., a system configuration for realizing wall surface linearity monitor. In the present configuration, a separate hub 42xe2x80x2 is required. In addition, like the case of using the RS-232C cables 5xe2x80x2, cables corresponding in number to the GPS receivers are required in wiring between the hub 42xe2x80x2 and respective GPS receivers 1axe2x80x2, limiting the laying of the cables.
The present invention is to solve problems in the prior art, and an object of the invention is to provide a GPS receiving system, GPS receiver and recording medium, which can use a communication scheme not subjected to 1:1 communication restriction when GPS is used in such a monitor system as to perform position monitoring with use of a plurality of GPS receivers, and which can realize wiring saving of LAN cables upon formation of a LAN.
In accordance with an aspect of the present invention, there is provided a GPS receiving system which has a plurality of GPS receivers having GPS antennas thereon, a GPS data processing apparatus, and cables for connection between the GPS receivers and GPS data processing apparatus, said GPS receivers each having a LAN I/F other than an RS-232C communication port provided in an input/output I/F.
In an embodiment, the above GPS receiver has an Ethernet I/F in the input/output I/F.
And in an embodiment, the above GPS receiver incorporates a hub having 10BASE-T and 10BASE-2.
Further, in an embodiment, the above GPS receiver has a CAN I/F in the input/output I/F.
In an embodiment, the above GPS receiver also has software which externally receives an initializing command and a data acquisition command to the GPS receiver via the LAN I/F of the input/output I/F to control the GPS receiver.
In accordance with another aspect of the present invention, there is provided a GPS receiver for use in a GPS receiving system which includes a plurality of such GPS receivers having GPS antennas mounted thereto, a GPS data processing apparatus and cables for connection between the GPS receivers and GPS data processing apparatus, the GPS receiver having an Ethernet I/F in a LAN I/F.
In accordance with a further aspect of the present invention, there is provided a GPS receiver for use in a GPS receiving system which includes a plurality of such GPS receivers having GPS antennas mounted thereto, a GPS data processing apparatus and cables for connection between the GPS receivers and GPS data processing apparatus, the GPS receiver having a CAN I/F in a LAN I/F.
In accordance with a still further aspect of the present invention, there is provided a recording medium for use in a GPS receiving system which includes a plurality of such GPS receivers having GPS antennas mounted thereto, a GPS data processing apparatus and cables for connection between the GPS receivers and GPS data processing apparatus, a program being provided to cause a computer to perform a function of externally receiving an initializing command and a data acquisition command to the GPS receiver to control the GPS receiver, the program being recorded in the recording medium to be read by the computer.